Arny, T. (2004). Explorations: Stars, galaxies, and planets (Updated ed.). McGraw-Hill.
Cita Chicago (17th ed.)Arny, Thomas. Explorations: Stars, Galaxies, and Planets. Updated ed. Boston: McGraw-Hill, 2004.
Cita MLA (8th ed.)Arny, Thomas. Explorations: Stars, Galaxies, and Planets. Updated ed. McGraw-Hill, 2004.
Atenció: Aquestes cites poden no estar 100% correctes.